This invention relates to a method and tool for plugging a cut pipe so that a fitting can be soldered to the cut pipe.
Soldering of copper pipe for the attachment of fittings in a water plumbing system is a simple and effective procedure. However, it cannot take place in the presence of water and even small quantities of water remaining in the pipe or running to the fitting during the soldering process can prevent the formation of a properly soldered joint.
It is usually necessary, therefore, to drain completely the plumbing system in which it is intended to add a fitting or to repair a broken pipe. In a normal household situation this is an inefficient but acceptable procedure because the amount of water involved in the pipes of the system is relatively small. Even in this case, however, small amounts of water can continue to run through the pipe even after the major amount of water has been fully drained.
In a major plumbing network, for example in a large building, it is most inconvenient to drain the system firstly because there are large amounts of water involved and secondly because this would interfere with the normal working of the building.
It is one object of the present invention, therefore, to provide a method and plumbing tool for plugging a pipe after the pipe has been cut for the soldering of a fitting to the cut end.
According to a first aspect of the invention, therefore, there is provided a plumbing tool for use in plugging a cut pipe for attachment of a fitting to the cut end of the pipe, the tool comprising a shaft, a sleeve surrounding the shaft, a screw threaded portion at one end of the shaft, a nut for engaging the screw threaded portion, a cylindrical resilient plug member for mounting on the end of the shaft remote from the screw threaded portion and arranged such that rotation of the nut and the screw threaded portion causes relative axial movement of the sleeve and the shaft axially compressing the resilient plug member so that the plug expands radially into contact with the inside surface of the pipe to plug the pipe, the radial extent of the shaft, sleeve, nut and plug being less than that of the pipe, and a stop member removably and axially adjustably mountable on the sleeve for locating the position of the plug member PG,4 and nut relative to the end of the pipe.
According to a second aspect of the invention, there is provided a plumbing tool for use in plugging a cut pipe for attachment of a fitting to the cut end of the pipe, the tool comprising a shaft, a sleeve surrounding the shaft, a screw threaded portion at one end of the shaft, a nut engaging the screw threaded portion, a cylindrical resilient plug member for mounting on the end of the shaft remote from the screw threaded portion and arranged such that rotation of the nut and the screw threaded portion causes relative axial movement of the sleeve and the shaft axially compressing the resilient plug member so that the plug expands radially into contact with the inside surface of the pipe to plug the pipe, the radial extent of the shaft, sleeve, nut and plug being less than that of the pipe, and the length of the shaft being greater thn the length of a fitting for the pipe plus four inches whereby the plug member can be located within the pipe at least four inches from the fitting while the nut projects from the end of the fitting remote from the pipe.
According to a third aspect of the invention, there is provided a kit of parts for use in plugging cut pipes for attachment of a fitting to the cut end of pipe comprising two shafts, each having a sleeve therearound, a screw threaded portion at one end of the shaft and a nut for engaging the screw threaded portion, and a plurality of cylindrical resilient plug members in a range of diameters from half inch through two and a half inches each for mounting in turn on the end of one of the shafts remote from the screw threaded portion and arranged such that rotation of the nut on the screw threaded portion causes relative axial movement between the sleeve and the shaft axially compressing the resilient plug member so that it radially expands into contact with the inside surface of the pipe to plug the pipe, the diametrical extent of the shafts, sleeves and nuts being less than one half inch, the length of one of the shafts being greater than the length of a fitting for a two and a half inch pipe plus four inches whereby the plug member can be located within the pipe at least four inches from the fitting while the nut projects from the end of the fitting remote from the pipe and the length of the other shaft being shorter than the first shaft and a stop member removably and axially adjustably mountable on the sleeve of the shafts for locating the position of the plug member and nut relative to the end of the pipe.
According to a fourth aspect of the invention there is provided a method of attaching a fitting to a pipe using a tool for plugging the pipe comprising a shaft, a sleeve surrounding the shaft, a screw threaded portion at one end of the shaft, a nut for engaging the screw threaded portion, a cylindrical resilient plug member for mounting on the end of the shaft remote from the screw threaded portion and arranged such that rotation of the nut and the screw threaded portion causes relative axial movement of the sleeve and the shaft axially compressing the resilient plug member so that the plug expands radially into contact with the inside surface of the pipe to plug the pipe, the radial extent of the shaft, sleeve, nut and plug being less than that of the pipe, the method comprising attaching a stop member to the shaft at such a position that with the shaft extending through the fitting, the nut is just exposed, cutting the pipe, inserting the plug member and shaft into the pipe until the stop engages the end of the pipe, rotating the nut to radially expand the plug to plug the pipe, the length of the shaft being such that the plug member is located within the pipe at least four inches from the end of the pipe, soldering the end of the pipe to the fitting and removing the plug member and shaft from the pipe through the fitting.
The invention therefore provides a number of advantages. Firstly, it enables the plug to be accurately located within the pipe after it has been cut and while the water is flowing from the pipe so that after the fitting has been applied to the pipe, the nut is still exposed to allow the plug to be removed and also the plug itself is spaced as far as possible from the point of application of heat for the soldering function.
Secondly, the tool is designed particularly for use in soldering copper pipe in that the length of the shaft and sleeve is sufficient such that it can accommodate the fitting and also space the plug from the end of the pipe where the heat is applied in the soldering technique sufficiently so that the plug is undamaged by the heat. Furthermore, the plug itself is manufactured from a material which is more resistant to heat than conventional rubber.
It will be appreciated that the fittings for particular diameter of pipe have a particular length so that the fittings for, for example, a two and a half inch pipe, are considerably longer than those for, for example, a half inch pipe.
The fitting can include a valve so that after the plug has been removed, the valve can be closed off to prevent further escape of water. In this regard the plug, shaft and sleeve all must be considerably less than the diameter of the pipe in order to pass through the seat of the valve fitting. In view of this small diameter of the plug, it is important that the plug can be radially expanded from a position in which it is out of contact with the inner surface of the pipe.
Thus, there can be provided lock washers for locking the sleeve to the plug and the plug to the shaft to prevent rotation of the shaft relative to the sleeve so that rotation of the nut drives the sleeve axially while the sleeve is held against rotation.
In addition, in areas where the escape of any water could be damaging to finished decorations, the tool can also include a bag which can be mounted on the pipe and held away from the pipe by supports so that the operative can place his hands through openings in the bag to work upon the pipe inside the bag. A connection at the bottom of the bag can run the water which escapes from the pipe after cutting and before the plug is inserted to a drain or to another collecting device.
With the foregoing in view, and other advantages as will become apparent to those skilled in the art to which this invention relates as this specification proceeds, the invention is herein described by reference to the accompanying drawings forming a part hereof, which includes a description of the best mode known to the applicant and of the preferred typical embodiment of the principles of the present invention, in which: